MYC and breast cancer: MiR‐20a, which belongs to miR‐17‐92 cluster, was regulated by c‐Myc and involved in tumorigenesis in breast cancer.35 MiR‐20a could inhibit the expression of tumor‐suppressor ZBTB4 protein, which was related to prognosis of breast cancer.36 We observed, for the first time to our knowledge, the relationship between miR‐20a and response to chemotherapy in breast cancer, and the underlying molecular mechanism warrants further studies.